<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Jquery</title>
    <script type="text/javascript" src="js/jquery-1.7.1.min.js"></script>
    <script type="text/javascript">
		$(document).ready(function(){
			function validate_email(email){
				$.post('php/checkEmail.php', {email: email}, function(data){
					$('#email_feedback').text(data);
				});
			}
			$('#email').focusin(function(){
				if($('#email').val()==''){
					$('#email_feedback').text('Go on, enter a valid email address ...');
				}else{
					validate_email($('#email').val());
				}
			}).blur(function(){
				$('#email_feedback').text('');
			}).keyup(function(){
				validate_email($('#email').val());
			});
		});
	</script>
	
</head>
<body>	
    Email <input type="text" id="email" /> <span id="email_feedback"></span>
</body>   
</html>
